1. Department of Medicine, Surgery and Pharmacy, University of Sassari, 07100 Sassari, Italy
2. Department of Internal Medicine, Azienda Ospedaliero Universitaria di Sassari, 07100 Sassari, Italy
3. Centralized Day Hospital of the Medical Area, Azienda Ospedaliero Universitaria di Sassari, viale San Pietro 8, 07100 Sassari, Italy
4. Department of Biomedical Sciences, Public Health-Laboratory of Biostatistics, University of Sassari, 07100 Sassari, Italy